Apparatus and method for singulating porous fuel cell layers using adhesive tape pick head

ABSTRACT

An apparatus and method provide for singulating thin and substantially porous material layers arranged in a stack. A pick head is positioned above the stack of material layers. An adhesive tape is stabilized against the pick head through use of a vacuum between the adhesive tape and the pick head. Contact is effected between the stabilized adhesive tape and the top material layer. The pick head is moved to move the top material layer from the stack to a predetermined location. While at the predetermined location, the adhesive tape is detached from the top material layer. The singulation apparatus and method are particularly well suited for destacking individual porous fluid transport layers (FTLs) from a magazine of FTLs during automated fuel cell assembly.

FIELD OF THE INVENTION

[0001] The present invention relates generally to manufacturing pick andplace devices and, more particularly, to an apparatus and method forsingulating porous layers of a fuel cell using an adhesive tape pickhead assembly.

BACKGROUND OF THE INVENTION

[0002] Various apparatuses have been developed to destack items from amagazine of such items in an automated fashion. Conventional destackingapparatuses typically employ suction cups or a vacuum to releasablyengage and transport layers of a given material during a destackingoperation. Although such conventional arrangements may be satisfactoryin certain applications, implementing known approaches for destackingrelatively thin materials having varying porosity renders conventionalarrangements unworkable.

[0003] Moreover, it is often desirable to automate, either partially orcompletely, a number of processes of a destacking operation. Manyconventional material handling and destacking apparatuses and methodsare not well suited for a high degree of automation, particularlydestacking processes which have tight positional tolerance requirements.

[0004] There is a need for improved material layer destackingapparatuses and methodologies. There is a further need for suchapparatuses and methodologies that can safely and precisely positiondestacked material layers of varying porosity in an automated assemblyenvironment, such as in an automated fuel cell assembly plant. Thepresent invention fulfills these and other needs.

SUMMARY OF THE INVENTION

[0005] The present invention is directed to an apparatus and method ofsingulating thin and substantially porous material layers arranged in astack. According to a method of the present invention, a pick head ispositioned above the stack of material layers. An adhesive tape isstabilized against the pick head through use of a vacuum between theadhesive tape and the pick head. Contact is effected between thestabilized adhesive tape and the top material layer of the stack. Thepick head is moved so as to move the top material layer from the stackto a predetermined location. While at the predetermined location, theadhesive tape is detached from the top material layer.

[0006] An apparatus of the present invention provides for singulatingporous material layers arranged in a stack. The apparatus includes apick head comprising a pick region, a stripper mechanism situatedproximate the pick region, and a vacuum port located at the pick region.The vacuum port is adapted for coupling to a vacuum system. A tape drivemechanism is employed to control movement of an adhesive tape proximatethe vacuum port at the pick region. A positioning system supports thepick head, and is controllable to move the pick head vertically andhorizontally.

[0007] A controller is programmed to control the positioning system tomove the pick head so that the adhesive tape contacts the top porousmaterial layer. The adhesive tape is stabilized at the pick region by avacuum between the adhesive tape and the pick region. The controller isprogrammed to further control the positioning system to move the pickhead to a predetermined location. At the predetermined location, thestripper mechanism actuates to detach the top porous material layer fromthe adhesive tape. The controller is programmed to effect repeatedsingulation of the porous material layers from the stack. Thesingulation processes are repeated for subsequent material layers at thetop of the stack. The singulation apparatus and method are particularlywell suited for destacking individual porous fluid transport layers(FTLs) from a magazine of FTLs during automated fuel cell assembly.

[0008] The above summary of the present invention is not intended todescribe each embodiment or every implementation of the presentinvention. Advantages and attainments, together with a more completeunderstanding of the invention, will become apparent and appreciated byreferring to the following detailed description and claims taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is an illustration of a fuel cell and its constituentlayers;

[0010]FIG. 2 is a perspective view of a pick head assembly mounted on arobot in accordance with an embodiment of the present invention, therobot controllable to move the pick head assembly vertically andhorizontally;

[0011]FIG. 3 is a perspective view of a pick head assembly comprising apair of pick heads and a common tape drive mechanism that presents anadhesive tape across each of the pick heads in accordance with anembodiment of the present invention;

[0012]FIG. 4a is a top view of the wind-up mechanism shown in FIG. 3,the view of FIG. 4a showing a portion of a linkage assembly of thewind-up mechanism;

[0013]FIG. 4b is a front view of the wind-up mechanism shown in FIG. 3;

[0014]FIG. 4c is a side view of the linkage assembly partially shown inFIG. 4a;

[0015]FIG. 4d is a rear view of the linkage assembly partially shown inFIG. 4a;

[0016]FIG. 5a is a top view of the unwind mechanism shown in FIG. 3, theview of FIG. 5a showing a portion of an unwind assembly of the unwindmechanism;

[0017]FIG. 5b is a front view of the unwind mechanism shown in FIG. 3;

[0018]FIG. 5c is a side view of the unwind assembly partially shown inFIG. 5a; and

[0019]FIG. 5d is a rear view of the unwind assembly partially shown inFIG. 5a.

[0020] While the invention is amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It is to be understood,however, that the intention is not to limit the invention to theparticular embodiments described. On the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

[0021] In the following description of the illustrated embodiments,reference is made to the accompanying drawings which form a part hereof,and in which is shown by way of illustration, various embodiments inwhich the invention may be practiced. It is to be understood that theembodiments may be utilized and structural changes may be made withoutdeparting from the scope of the present invention.

[0022] A singulation apparatus and methodology of the present inventioncan be employed to singulate individual layers of relatively thinmaterial and to move singulated thin material layers to a predeterminedlocation with high precision. In particular, a singulation apparatus andmethodology of the present invention is well suited for destackingindividual thin material layers which are substantially porous. Forexample, certain material layers used to construct a fuel cell can havea thickness of one or two thousandths of an inch (e.g., about 0.001inches). These material layers can be porous and, in addition, may bebrittle. One skilled in the art will readily appreciate that destackingand transporting relatively thin layers of material, particularly porousand brittle material layers, both accurately and safely is a significantchallenge. These challenges are presently facing those attempting toautomate the process of fabricating fuel cells.

[0023] A singulation apparatus and methodology of the present inventionprovides for the safe and precise singulation of thin, porous materiallayers during automated processing of such material layers. Moreover,principles of the present invention may also be applied to singulate andaccurately position non-porous material layers during automatedprocessing of such material layers.

[0024] As indicated above, a singulation apparatus and methodology ofthe present invention can be employed to facilitate automatedsingulation and positioning of material layers defining a fuel cell or aportion of a fuel cell. A fuel cell is an electrochemical device thatcombines hydrogen fuel and oxygen from the air to produce electricity,heat, and water. Fuel cells do not utilize combustion, and as such, fuelcells produce little if any hazardous effluents. Fuel cells converthydrogen fuel and oxygen directly into electricity, and can be operatedat much higher efficiencies than internal combustion electricgenerators, for example.

[0025] A typical fuel cell is depicted in FIG. 1. The fuel cell 10 shownin FIG. 1 includes a first fluid transport layer 12 adjacent an anode14. Adjacent the anode 14 is an electrolyte membrane 16. A cathode 18 issituated adjacent the electrolyte membrane 16, and a second fluidtransport layer 19 is situated adjacent the cathode 18. In operation,hydrogen fuel is introduced into the anode portion of the fuel cell 10,passing through the first fluid transport layer 12 and over the anode14. At the anode 14, the hydrogen fuel is separated into hydrogen ions(H⁺) and electrons (e⁻).

[0026] The electrolyte membrane 16 permits only the hydrogen ions orprotons to pass through the electrolyte membrane 16 to the cathodeportion of the fuel cell 10. The electrons cannot pass through theelectrolyte membrane 16 and, instead, flow through an externalelectrical circuit in the form of electric current. This current canpower an electric load 17, such as an electric motor, or be directed toan energy storage device, such as a rechargeable battery.

[0027] Oxygen flows into the cathode side of the fuel cell 10 via thesecond fluid transport layer 19. As the oxygen passes over the cathode18, oxygen, protons, and electrons combine to produce water and heat.

[0028] Individual fuel cells, such as that shown in FIG. 1, can becombined with a number of other fuel cells to form a fuel cell stack.The number of fuel cells within the stack determines the total voltageof the stack, and the surface area of each of the cells determines thetotal current. The total electrical power generated by a given fuel cellstack can be determined by multiplying the total stack voltage by totalcurrent.

[0029] A singulation apparatus and methodology of the present inventioncan be employed to facilitate automated destacking and positioning ofmaterial layers in the construction of fuel cells of varyingtechnologies. For example, a singulation apparatus and methodology ofthe present invention can be employed to singulate material layers usedto construct proton exchange membrane (PEM) fuel cells. PEM fuel cellsoperate at relatively low temperatures (about 175 degrees F.), have highpower density, can vary their output quickly to meet shifts in powerdemand, and are well suited for applications where quick startup isrequired, such as in automobiles for example.

[0030] The proton exchange membrane used in a PEM fuel cell is a thinplastic sheet that allows hydrogen ions to pass through it. The membraneis coated on both sides with highly dispersed metal or metal alloyparticles (e.g., platinum or platinum/ruthenium) that are activecatalysts. The electrolyte used is typically a solid organic polymerpoly-perfluorosulfonic acid. Use of a solid electrolyte is advantageousbecause it reduces corrosion and management problems.

[0031] Hydrogen is fed to the anode side of the fuel cell where thecatalyst encourages the hydrogen ions to release electrons and becomehydrogen ions (protons). The electrons travel in the form of an electriccurrent that can be utilized before it returns to the cathode side ofthe fuel cell where oxygen has been introduced. At the same time, theprotons diffuse through the membrane to the cathode, where the hydrogenions are recombined and reacted with oxygen to produce water.

[0032] According to one PEM fuel cell construction, a PEM layer issandwiched between a pair of fluid transport layers, such as diffusecurrent collectors or gas diffusion layers for example. An anode issituated between a first FTL and the membrane, and a cathode is situatedbetween the membrane and a second FTL. In one configuration, a PEM layeris fabricated to include an anode catalyst coating on one surface and acathode catalyst coating on the other surface. According to anotherconfiguration, the first and second FTLs are fabricated to include ananode and cathode catalyst coating, respectively. In yet anotherconfiguration, an anode catalyst coating can be disposed partially onthe first FTL and partially on one surface of the PEM, and a cathodecatalyst coating can be disposed partially on the second FTL andpartially on the other surface of the PEM. The five layer constructdefined by the first FTL/anode/PEM/cathode/second FTL is referred to asa membrane electrode assembly (MEA).

[0033] The FTLs are typically fabricated from a carbon fiber paper ornon-woven material. Depending on the product construction, the FTLs canhave carbon particle coatings on one side. The FTLs, as discussed above,can be fabricated to include or exclude a catalyst coating. The FTLs,according to this product construction, are both porous and brittle. Asingulation apparatus and methodology consistent with the principles ofthe present invention is particularly well suited for destacking andpositioning thin fuel cell layers, such as PEM layers and FTLs forexample, during automated fuel cell assembly.

[0034] Direct methanol fuel cells (DMFC) are similar to PEM cells inthat they both use a polymer membrane as the electrolyte. In a DMFC,however, the anode catalyst itself draws the hydrogen from liquidmethanol fuel, eliminating the need for a fuel reformer. DMFCs typicallyoperate at a temperature between 120-190 degrees F.

[0035] Molten carbonate fuel cells (MCFC) use a liquid solution oflithium, sodium and/or potassium carbonates, soaked in a matrix for anelectrolyte. MCFCs operate at about 1,200 degrees F. The high operatingtemperature is needed to achieve sufficient conductivity of theelectrolyte. Because of this high temperature, noble metal catalysts arenot required for the cell's electrochemical oxidation and reductionprocesses. MCFCs are typically operated on hydrogen, carbon monoxide,natural gas, propane, landfill gas, marine diesel, and simulated coalgasification products.

[0036] A solid oxide fuel cell (SOFC) typically employs a hard ceramicmaterial of solid zirconium oxide and a small amount of ytrria, insteadof a liquid electrolyte, allowing operating temperatures to reach 1,800degrees F.

[0037] In regenerative fuel cells, water is separated into hydrogen andoxygen by a solar-powered electrolyser. The hydrogen and oxygen are fedinto the regenerative fuel cell which generates electricity, heat, andwater. The water is then recirculated back to the solar-poweredelectrolyser and the process is repeated.

[0038] A protonic ceramic fuel cell (PCFC) employs a ceramic electrolytematerial that exhibits high protonic conductivity at elevatedtemperatures. PCFCs operate at about 1,300 degrees F. PCFCs can operateat high temperatures and electrochemically oxidize fossil fuels directlyto the anode. Gaseous molecules of the hydrocarbon fuel are absorbed onthe surface of the anode in the presence of water vapor, and hydrogenions are efficiently stripped off to be absorbed into the electrolyte,with carbon dioxide as the primary reaction product. These and otherfuel cell technologies can be constructed from material layerssingulated and positioned by use of a singulation apparatus andmethodology in accordance with the present invention.

[0039] In accordance with one application, a singulation apparatus andmethodology of the present invention are employed to pick a single fluidtransport layer (FTL), such as a gas diffusion layer or diffuse currentcollector, off the top of a stack of FTLs and place the singulated FTLin an precise location for inclusion within a fuel cell membraneelectrode assembly, such as a PEM type MEA. In MEA construction, forexample, picking and placing of FTLs needs to be accomplished carefullyand precisely. There are typically very tight locational tolerances whenconstructing an MEA stack (e.g., positional tolerances ranging betweenabout 0.01 inches and about 0.02 inches). FTLs are porous and typicallybrittle. Use of conventional vacuum techniques to destack an FTL from amagazine of FTLs would result in picking up several FTLs. An apparatusand methodology of the present invention advantageously provides for thesingulation of an FTL from a stack of FTLs, and further provides for theplacement of singulated FTLs at a preestablished location with highprecision.

[0040] According to an embodiment of the present invention, one, two, ormore adhesive tape pick heads are used in conjunction with a servomotordriven robot to singulate FTLs or other thin porous material layers andto transport individual FTLs to a desired location with high accuracy.The robot is preferably controllable to move the pick heads inhorizontal and vertical directions. A horizontal servomotor of the robotemploys a rack and pinion system with linear bearing to precisely locatethe pick heads in the horizontal direction. A vertical servomotor of therobot employs a ball screw assembly with linear bearing to locate thepick heads in the vertical direction.

[0041] Because the product to be handled in accordance with thisembodiment is porous and must be picked out of a magazine, an adhesivetape system is employed in the pick head assembly to destack theproduct. The pick head assembly incorporates wind and unwind mechanismsto index an adhesive tape by a small amount after each pick cycle,thereby maintaining the needed adhesion capability of the pick headassembly. A distance sensor, such as an ultrasonic sensor, is used todetermine stack height and the vertical travel needed to engage theadhesive tape with the product. A stripping mechanism, such as stripperfeet, is used to separate the product from the adhesive tape at thepredetermined destination location.

[0042] Due to the brittle nature of the product according to thisapplication, one or more springs are preferably used to counter theweight of the pick heads. A web break sensor detects if the adhesivetape breaks or the unwind mechanism dispenses all of the availableadhesive tape. Vacuum is advantageously used at the pick head tostabilize the adhesive tape and prevent the adhesive tape and FTL frommoving relative to the pick head. The incorporation of vacuum to controlthe adhesive tape at the pick head, and therefore maintain preciselocational control of the FTL adhered thereto, combined with servomotorpositioning of the robot provides for a high precision pick and placeapparatus.

[0043] Turning now to FIG. 2, there is illustrated an adhesive tape pickhead assembly 40 in accordance with an embodiment of the presentinvention. According to this embodiment, the pick head assembly 40comprises two pairs of pick heads for a total of four pick heads thatoperate in conjunction to pick and place thin porous material layers,such as FTLs, during an automated destacking and placement operation.The pick head assembly 40 is shown mounted via mounts 41 to a support 34extending from support arms 32 of a robot 30.

[0044] Movement of the robot 30, and therefore the pick head assembly40, is effected by a positioning system 31 under control of a controller35. Controller 35 is a programmable device, such as a processor, thatexecutes program instructions to coordinate the activities of variouselements of the robot 30. The controller 35 may be an on-board device ormay be located remotely of the robot 30. If located remotely, thecontroller 35 is coupled to the robot 30 using an appropriate hardwiredor wireless connection.

[0045] The positioning system 31 includes a vertical positioning systemand a horizontal positioning system. The vertical positioning systemincludes a vertical servomotor 37 which cooperates with a ball screwassembly (not shown) to controllably move the pick head assembly 40 inthe vertical direction. The horizontal positioning system includes ahorizontal servomotor 39 which cooperates with a rack and pinion system(not shown) to controllably move the pick head assembly 40 in thehorizontal direction.

[0046]FIG. 3 is a perspective view of a pick head assembly 40 comprisinga pair of pick heads 50 and a common tape drive mechanism 43 thatadvances an adhesive tape 65 across each of the pick heads 50 inaccordance with an embodiment of the present invention. As shown in FIG.3, and as described below, the pick head assembly 40 includes a firstpick head assembly 40A and a second pick head assembly 40B. It isunderstood that a pick head assembly 40 of the present invention mayinclude a single pick head 50 or greater than two pick heads 50. Forexample, FIG. 2 shows four pick heads 50 arranged on the robot 30 tooperate cooperatively.

[0047] In the case of pick head assembly 40 in which a single pick head50 is employed, it is understood that both the unwind and wind-upsections of the tape drive mechanism 43 are typically integrated withinthe single pick head assembly 40. Moreover, and in accordance withanother embodiment, the tape drive mechanism 43 need not be mounteddirectly to the pick head assembly 40, but may instead be supported byan external support system, such that adhesive tape 65 is fed to thepick head assembly 40 to present fresh adhesive at the pick head 50 foreach pickup cycle.

[0048] The first pick head assembly 40A and second pick head assembly40B shown in FIG. 3 each incorporate a pick head 50 which includes avacuum port 52 at a distal end and an inlet 72 at a proximal end of thepick head 50. A chamber of the pick head 50 extends between the inlet 72and the vacuum port 52. The inlet 72 is adapted to connect with a vacuumsystem (not shown) which is controlled to selectively provide a vacuumbetween the vacuum port 52 situated at a pick region of the pick head 50and a portion of the adhesive tape 65 moved into proximity with thevacuum port 52.

[0049] Stripper feet 54 are situated on each of two sides of the vacuumport 52. The stripper feet 54 are shown in a retracted configuration inFIG. 3, and remain in the retracted configuration until after theproduct has been picked from the product magazine and moved to itsintended destination location. When the pick head 50 is properlypositioned at the destination location, the stripper feet 54 areextended beyond a plane of the vacuum port 52, which cause the adhesivetape 65 to separate from the product without disturbing the orientationof the product.

[0050] A distance sensor 60 is situated on the pick head assembly 40 andis used to determine the height of the product stack. The distancesensor 60 cooperates with the controller 35 or other processor tocompute the vertical travel needed to effect engagement between theadhesive tape 65 presented at the vacuum port 52 and the top product ofthe product stack. The distance sensor 60 is preferably an ultrasonicsensor, but may also be an optical sensor.

[0051] In the embodiment depicted in FIG. 3, the first pick headassembly 40A incorporates a wind-up mechanism 42 and the second pickhead assembly 40B incorporates an unwind mechanism 44. The wind-upmechanism 42 of the first pick head assembly 40A shown in FIG. 3 willnow be described in greater detail with reference to FIGS. 4a-4 d. FIG.4a is a top view of the first pick head assembly 40A shown in FIG. 3.FIG. 4b is a front view showing of the wind-up mechanism 42 shown inFIG. 3. FIG. 4c is a side view of a linkage assembly 74 partially shownin the top view of FIG. 4a. FIG. 4d is a rear view of the linkageassembly 74 shown in FIG. 4c.

[0052] The wind-up mechanism 42 includes a wind-up roll 45 that receivesspent adhesive tape 65 fed to the pick head 50 via an idler roll 46. Theidler roll 46 of the wind-up mechanism 42, according to this embodiment,receives adhesive tape 65 from an idler roll 47 and unwind roll 48 ofthe unwind mechanism 44. The wind-up mechanism 42 employs a rollerclutch needle bearing 71 which cooperates with a brake 78 to index theadhesive tape 65 in a forward direction from the unwind roll 48 to thewind-up roll 45. A pneumatic cylinder 77 cooperates with a 6-bar linkage76 to advance the core of the wind-up roll 45. In one configuration, thepneumatic cylinder 77 cooperates with a 6-bar linkage 76 to advance thecore of the wind-up roll 45 and concurrently actuates the stripper feet54 to move to their extended configuration to strip the product off thepick head 50.

[0053] As previously discussed, vacuum is applied at the vacuum port 52via chamber 72 to stabilize the adhesive tape 65 presented proximate thevacuum port 52. Stabilizing the adhesive tape 65 at the pick head 50when engaging a porous product increases the precision by which suchproduct can be destacked and repositioned.

[0054] A spring 49 is employed between a vertical portion of the mount41 and the first pick head assembly 40A to counter balance the weight ofthe first pick head assembly 40A. This weight counter balancingmechanism significantly reduces or prevents damage to brittle product,such as fluid transport layers of a fuel cell, when the pick head 50 isbrought into contact with the product. The first pick head assembly 40Ais compliant vertically, through use of vertical shafts comprisingslides 51 and linear bearings 53, to allow for slight over travel of therobot's vertical servomotor 37 to ensure sufficient contact between thepick head 50 and the product.

[0055] The unwind mechanism 44 of the second pick head assembly 40Bshown in FIG. 3 will now be described in greater detail with referenceto FIGS. 5a-5 d. FIG. 5a is a top view of the second pick head assembly40B shown in FIG. 3, and provides a partial showing of a portion of anunwind assembly 80 of the unwind mechanism 44. FIG. 5b is a front viewof the unwind mechanism 44 shown in FIG. 5a. FIG. 5c is a side view ofthe unwind assembly 80 partially shown in FIG. 5a. FIG. 5d is a rearview of the unwind assembly 80 shown in FIG. 5c.

[0056] The unwind mechanism 44 includes an unwind roll 48 that providesunused adhesive tape 65 to the pick head 50. The partially used adhesivetape 65 advances from the pick head 50, to the idler roll 47, and to theidler roll 46 of the wind-up mechanism 42. The wind-up mechanism 42,according to this embodiment, receives adhesive tape 65 from the idlerroll 47 and unwind roll 48 of the unwind mechanism 44.

[0057] In one configuration, the length of the adhesive tape 65 betweenthe pick heads 50 of the first and second pick head assemblies 40A, 40Bis selected so that sections of the adhesive tape 65 used by the pickhead 50 of the first pick head assembly 40A skip past the pick head 50of the second pick head assembly 40B. In this configuration, freshadhesive is presented at the vacuum ports 52 of the first and secondpick head assemblies 40A, 40B. In another configuration, the adhesivetape 65 employs an adhesive that provides sufficient adhesion for two ormore picking cycles, in which case the section of the adhesive tape usedby the first pick head 50 is simply advanced for use by each subsequentpick head 50.

[0058] The unwind mechanism 44 preferably uses the same vacuum system asthe wind-up mechanism 42 to stabilize the adhesive tape 65 via a vacuumat the vacuum port 52 of the pick head 50. The unwind mechanism 44employs a brake 85 to control the tension in the adhesive tape 65. Apneumatic cylinder 86 is used to extend the stripper feet 54 to stripthe product off the pick head 50 when the product reaches its intendeddestination location.

[0059] A tape break detection system is provided at the unwind mechanism44. In one configuration, a tape sensor 62, which may be a proximityswitch operating in cooperation with flags 84, senses when a breakoccurs in the adhesive tape 65 or when the all of the adhesive tape 65has been dispensed from the unwind roll 48.

[0060] A spring 49 is employed between a vertical portion of the mount41 and the second pick head assembly 40B to counter balance the weightof the second pick head assembly 40B to prevent damage to brittleproduct when the pick head 50 is brought into contact with the product.The second pick head assembly 40B is compliant vertically, through useof vertical shafts comprising slides 51 and linear bearings 53, to allowfor slight over travel of the robot's vertical servomotor 37 to ensuresufficient contact between the pick head 50 and the product.

[0061] A process of singulating an FTL according to an embodiment of thepresent invention will now be described. It is understood that two tofour pick heads 50 are typically employed to pick and place FTLs from anFTL stack to a desired position, although a single pick head may beused. Initially, the pick heads 50 are positioned above a magazinecontaining a stack of FTLs. At this stage, the stripper feet 54 areretracted and vacuum at the vacuum ports 52 are actively stabilizingadhesive tape 65 against the respective pick heads 50. The distancesensor 60 determines the distance to the top FTL of the stack of FTLs.The vertical servomotor 37 of the robot 30 lowers the pick heads 50 bythe determined distance plus a small additional amount to ensure captureof the top FTL by the pick heads 50. As was discussed above, the pickheads 50 have vertical compliance built in to handle over travel.

[0062] After the adhesive tape 65 stabilized at the pick region of therespective pick heads 50 engages the top FTL, the vertical servomotor 37of the robot 30 moves the top FTL upward and the robot's horizontalservomotor 39 moves the top FTL to the desired position. The stripperfeet 54 of the respective pick heads 50 are extended to strip the topFTL from the pick heads 50 at the desired position. Extending thestripper feet 54 also rotates the wind-up mechanism's indexing arm back.The vertical servomotor 37 then lifts the pick heads 50 away from thetop FTL. The vacuum at the vacuum ports 52 is turned off of the adhesivetape 65, and the stripper feet 54 are retracted. This movement alsoadvances the adhesive tape 65 forward. Vacuum is once again turned on tostabilize the adhesive tape 65, and the horizontal servomotor 39 returnsto the magazine in a ready state to handle the next top FTL of the FTLstack.

[0063] The foregoing description of the various embodiments of theinvention has been presented for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise form disclosed. Many modifications andvariations are possible in light of the above teaching. It is intendedthat the scope of the invention be limited not by this detaileddescription, but rather by the claims appended hereto.

What is claimed is:
 1. A method of singulating a plurality of porousfuel cell fluid transport layers (FTLs) arranged in a stack (FTL stack),the FTL stack comprising a top FTL, the method comprising: positioning apick head above the FTL stack; stabilizing an adhesive tape against thepick head through use of a vacuum between the adhesive tape and the pickhead; effecting contact between the stabilized adhesive tape and the topFTL; moving the pick head to move the top FTL from the FTL stack to apredetermined location; detaching, while at the predetermined location,the adhesive tape from the top FTL; and repeating the positioning,stabilizing, effecting, moving, and detaching processes for subsequenttop FTLs.
 2. The method of claim 1, further comprising determining adistance between the pick head and the top FTL, wherein effectingcontact further comprises moving the pick head by at least thedetermined distance such that the adhesive tape contacts the top FTL. 3.The method of claim 2, wherein determining the distance comprisesultrasonically determining the distance between the pick head and thetop FTL.
 4. The method of claim 1, wherein detaching the adhesive tapecomprises extending a stripper mechanism of the pick head to effectdetachment of the adhesive tape from the top FTL.
 5. The method of claim4, wherein detaching the adhesive tape further comprises retracting thestripper mechanism after detaching the adhesive tape from the top FTL.6. The method of claim 1, further comprising advancing the adhesive tapeto present unused adhesive proximate the pick head after detaching theadhesive tape from the top FTL.
 7. The method of claim 6, furthercomprising removing the vacuum between the adhesive tape and the pickhead after detaching the adhesive tape from the top FTL and prior toadvancing the adhesive tape.
 8. The method of claim 1, wherein the FTLstack is stationary, and effecting contact comprises moving the pickhead so that the adhesive tape contacts the top FTL.
 9. The method ofclaim 1, wherein effecting contact comprises displacing the pick headvertically so that the adhesive tape contacts the top FTL, and movingthe pick head comprises moving the pick head horizontally to move thetop FTL to the predetermined location.
 10. The method of claim 1,further comprising detecting presence or absence of the adhesive tape atthe pick head.
 11. The method of claim 1, wherein detaching the adhesivetape from the top FTL comprises detaching the adhesive tape from the topFTL at the predetermined location with a positional tolerance rangingbetween about 0.01 inches and about 0.02 inches.
 12. A method ofsingulating a plurality of thin and substantially porous material layersarranged in a stack, the stack of material layers comprising a topmaterial layer, the method comprising: positioning a pick head above thestack of material layers; stabilizing an adhesive tape against the pickhead through use of a vacuum between the adhesive tape and the pickhead; effecting contact between the stabilized adhesive tape and the topmaterial layer; moving the pick head to move the top material layer fromthe stack to a predetermined location; detaching, while at thepredetermined location, the adhesive tape from the top material layer;and repeating the positioning, stabilizing, effecting, moving, anddetaching processes for subsequent top material layers.
 13. The methodof claim 12, further comprising determining a distance between the pickhead and the top material layer, wherein effecting contact furthercomprises moving the pick head by at least the determined distance suchthat the adhesive tape contacts the top material layer.
 14. The methodof claim 12, wherein determining the distance comprises ultrasonicallydetermining the distance between the pick head and the top materiallayer.
 15. The method of claim 12, wherein detaching the adhesive tapecomprises extending a stripper mechanism of the pick head to effectdetachment of the adhesive tape from the top material layer.
 16. Themethod of claim 15, wherein detaching the adhesive tape furthercomprises retracting the stripper mechanism after detaching the adhesivetape from the top material layer.
 17. The method of claim 12, furthercomprising advancing the adhesive tape to present unused adhesiveproximate the pick head after detaching the adhesive tape from the topmaterial layer.
 18. The method of claim 17, further comprising removingthe vacuum between the adhesive tape and the pick head after detachingthe adhesive tape from the top material layer and prior to advancing theadhesive tape.
 19. The method of claim 12, wherein the stack of materiallayers is stationary, and effecting contact comprises moving the pickhead so that the adhesive tape contacts the top material layer.
 20. Themethod of claim 12, wherein effecting contact comprises displacing thepick head vertically so that the adhesive tape contacts the top materiallayer, and moving the pick head comprises moving the pick headhorizontally to move the top material layer to the predeterminedlocation.
 21. The method of claim 12, further comprising detectingpresence or absence of the adhesive tape at the pick head.
 22. Themethod of claim 12, wherein detaching the adhesive tape from the topmaterial layer comprises detaching the adhesive tape from the topmaterial layer at the predetermined location with a positional toleranceranging between about 0.01 inches and about 0.02 inches.
 23. Anapparatus for singulating a plurality of porous fuel cell fluidtransport layers (FTLs) arranged in a stack (FTL stack), the FTL stackcomprising a top FTL, the apparatus comprising: a pick head comprising apick region, a stripper mechanism situated proximate the pick region,and a vacuum port located at the pick region, the vacuum port adaptedfor coupling to a vacuum system; a tape drive mechanism, the tape drivemechanism controlling movement of an adhesive tape proximate the vacuumport at the pick region; a positioning system that supports the pickhead, the positioning system controllable to move the pick headvertically and horizontally; and a controller, the controller programmedto control the positioning system to move the pick head so that theadhesive tape contacts the top FTL, the adhesive tape stabilized at thepick region by a vacuum between the adhesive tape and the pick region,the controller programmed to further control the positioning system tomove the pick head to a predetermined location, the stripper mechanismactuating to detach the top FTL from the adhesive tape at thepredetermined location.
 24. The apparatus of claim 23, wherein thecontroller is programmed to effect repeated singulation of FTLs from theFTL stack.
 25. The apparatus of claim 23, wherein the tape drivemechanism is connected to the pick head.
 26. The apparatus of claim 23,wherein the tape drive mechanism is separate from the pick head.
 27. Theapparatus of claim 23, wherein the tape drive mechanism comprises awind-up mechanism and an unwind mechanism, the wind-up and; unwindmechanisms cooperating to move the adhesive tape so that unused adhesiveof the adhesive tape is presented at the pick region.
 28. The apparatusof claim 27, wherein the wind-up and unwind mechanisms each comprise aroll, and the adhesive tape is unwound from the roll of the unwindmechanism and wound on the roll of the wind-up mechanism.
 29. Theapparatus of claim 27, wherein the wind-up mechanism comprises a rollerclutch needle bearing and a brake, the roller clutch needle bearing andbrake cooperating to index the adhesive tape in a forward direction fromthe unwind mechanism to the wind-up mechanism.
 30. The apparatus ofclaim 27, wherein the pick head comprises a pneumatic cylinder and alinkage, the pneumatic cylinder and linkage cooperating to advance theadhesive tape between the unwind mechanism and the wind-up mechanism.31. The apparatus of claim 23, wherein the pick head comprises apneumatic cylinder and a linkage, the pneumatic cylinder and linkagecooperating to actuate the stripper mechanism.
 32. The apparatus ofclaim 31, wherein the controller is programmed to control the pneumaticcylinder so that the stripper mechanism is actuated at the predeterminedlocation to detach the top FTL from the adhesive tape.
 33. The apparatusof claim 23, wherein the stripper mechanism comprises stripper feet. 34.The apparatus of claim 23, further comprising a distance sensor at thepick head, the distance sensor determining a distance between the pickhead and the top FTL.
 35. The apparatus of claim 34, wherein thedistance sensor comprises an ultrasonic sensor.
 36. The apparatus ofclaim 23, further comprising a sensor that senses presence or absence ofthe adhesive tape proximate the pick region.
 37. The apparatus of claim23, wherein the pick head comprises one or more springs mounted toprovide counter-balance for weight of the pick head.
 38. The apparatusof claim 23, wherein the pick head and tape drive mechanism define aunitary pick head unit, and a plurality of pick head units are supportedby the positioning system.
 39. The apparatus of claim 23, wherein thepositioning system comprises a vertical servomotor for moving the pickhead vertically, and a horizontal servomotor for moving the pick headhorizontally.
 40. The apparatus of claim 39, wherein the pick headcomprises vertical linear slides to allow for slight over travel of thevertical servomotor to ensure adequate contact between the adhesive tapeand the top FTL.
 41. The apparatus of claim 39, wherein the verticalservomotor is coupled to a rack and pinion arrangement, and thehorizontal servomotor is coupled to a ball screw assembly.
 42. Theapparatus of claim 23, wherein the apparatus includes a pair of the pickheads comprising a first pick head and a second pick head, and the tapedrive mechanism comprises an unwind mechanism mounted proximate thefirst pick head and a wind-up mechanism proximate the second pick head,the unwind and wind-up mechanisms cooperating to control movement of theadhesive tape proximate the vacuum port at the pick region of the firstand second pick heads, respectively.
 43. The apparatus of claim 42,wherein the first and second pick heads define a unitary pick headassembly.
 44. The apparatus of claim 42, wherein the first and secondpick heads define separate pick head assemblies.
 45. The apparatus ofclaim 23, wherein the positioning system detaches the top FTL from theadhesive tape at the predetermined location with a positional toleranceranging between about 0.01 inches and about 0.02 inches.
 46. Anapparatus for singulating a plurality of porous material layers arrangedin a stack, the stack comprising a top porous material layer, theapparatus comprising: a pick head comprising a pick region, a strippermechanism situated proximate the pick region, and a vacuum port locatedat the pick region, the vacuum port adapted for coupling to a vacuumsystem; a tape drive mechanism, the tape drive mechanism controllingmovement of an adhesive tape proximate the vacuum port at the pickregion; a positioning system that supports the pick head, thepositioning system controllable to move the pick head vertically andhorizontally; and a controller, the controller programmed to control thepositioning system to move the pick head so that the adhesive tapecontacts the top porous material layer, the adhesive tape stabilized atthe pick region by a vacuum between the adhesive tape and the pickregion, the controller programmed to further control the positioningsystem to move the pick head to a predetermined location, the strippermechanism actuating to detach the top porous material layer from theadhesive tape at the predetermined location.
 47. The apparatus of claim46, wherein the controller is programmed to effect repeated singulationof the porous material layers from the stack.
 48. The apparatus of claim46, wherein the tape drive mechanism is connected to the pick head. 49.The apparatus of claim 46, wherein the tape drive mechanism is separatefrom the pick head.
 50. The apparatus of claim 46, wherein the tapedrive mechanism comprises a wind-up mechanism and an unwind mechanism,the wind-up and unwind mechanisms cooperating to move the adhesive tapeso that unused adhesive of the adhesive tape is presented at the pickregion.
 51. The apparatus of claim 46, wherein the stripper mechanismcomprises stripper feet.
 52. The apparatus of claim 46, furthercomprising a distance sensor at the pick head, the distance sensordetermining a distance between the pick head and the top porous materiallayer.
 53. The apparatus of claim 52, wherein the distance sensorcomprises an ultrasonic sensor.
 54. The apparatus of claim 46, furthercomprising a sensor that senses presence or absence of the adhesive tapeproximate the pick region.
 55. The apparatus of claim 46, wherein thepick head comprises one or more springs mounted to providecounter-balance for weight of the pick head.
 56. The apparatus of claim46, wherein the pick head and tape drive mechanism define a unitary pickhead unit, and a plurality of pick head units are supported by thepositioning system.
 57. The apparatus of claim 46, wherein thepositioning system comprises a vertical servomotor for moving the pickhead vertically, and a horizontal servomotor for moving the pick headhorizontally.
 58. The apparatus of claim 57, wherein the pick headcomprises vertical linear slides to allow for slight over travel of thevertical servomotor to ensure adequate contact between the adhesive tapeand the top porous material layer.
 59. The apparatus of claim 57,wherein the vertical servomotor is coupled to a rack and pinionarrangement, and the horizontal servomotor is coupled to a ball screwassembly.
 60. The apparatus of claim 46, wherein the apparatus includesa pair of the pick heads comprising a first pick head and a second pickhead, and the tape drive mechanism comprises an unwind mechanism mountedproximate the first pick head and a wind-up mechanism proximate thesecond pick head, the unwind and wind-up mechanisms cooperating tocontrol movement of the adhesive tape proximate the vacuum port at thepick region of the first and second pick heads, respectively.
 61. Theapparatus of claim 60, wherein the first and second pick heads define aunitary pick head assembly.
 62. The apparatus of claim 60, wherein thefirst and second pick heads define separate pick head assemblies. 63.The apparatus of claim 46, wherein the positioning system detaches thetop porous material layer from the adhesive tape at the predeterminedlocation with a positional tolerance ranging between about 0.01 inchesand about 0.02 inches.